Causes, Symptoms and Treatments for Scabies

There are various treatments for the symptoms of scabies (intense itching, hives, and reddish epidermal ulcers). These are the result of the action of a mite that creates tunnels under the stratum corneum. 
Causes, Symptoms and Treatments for Scabies
Samuel Antonio Sánchez Amador

Written and verified by the biologist Samuel Antonio Sánchez Amador.

Last update: 27 May, 2022

There are various treatments for scabies, a parasite caused by the Sarcoptes scabiei var. hominins mite. This parasite has a close relationship with humans and the first reports of its existence date back to the 12th century. This disease occurs throughout the world, with outbreaks of cyclical incidence every 15 years.

According to the World Health Organization (WHO), approximately 200 million people worldwide experience scabies at any given time. In addition, estimates indicate that 10% of the population in low-income settings have this parasite.


The main sign of the disease is intense itching and it becomes more evident at night. It’s as unpleasant as it sounds. This is because the female mite digs tunnels in the patient’s outer layer of the skin and it triggers an allergic reaction by the immune system.

The U.S. National Library of Medicine shows the various clinical signs of scabies in humans. These include the following:

  • Severe itching, most often at night and in hot weather. The female mite is more active under the skin and it leads to discomfort.
  • Skin rash that’s more evident in the folds and between the fingers and toes. It’s most common in the armpits, under the breasts, inside the joints, and around the genital area.
  • Reddish ulcers on the skin, resulting from scratching and digging.
  • Thin furrowed lines on the skin due to the tunnels dug by the parasite.

Note that the rash usually spreads over the entire body in infants and young children and the parts most usually affected are the head, face, and neck.

The scabies parasite, Sarcoptes acaro
The mite can penetrate human skin and settle there; it’s a different variety from those that attack dogs and cats.

When to see a doctor?

The Mayo Clinic strongly advises consulting a doctor if you notice any symptoms of scabies. However, it isn’t too serious and so your main worry is just getting rid of it.

People often mistake dermatitis, local allergic reactions, and contact irritations for scabies. This is why you must consult a professional who can diagnose your individual case.

What causes scabies in humans?

As mentioned above, scabies in humans is caused by the Sarcoptes scabiei var. hominis mite. The females of this species measure 300 to 450 microns and are obligate parasites. What this means is they can’t survive without a host for more than four days.

The female and male of the species copulate on the skin of the host, after which the female begins to dig tunnels in the stratum corneum to lay her eggs. As studies indicate, the parasite has a predilection for certain areas of the skin, such as the underneath of the wrists, the ulnar border of the hand, and the interdigital areas.

Note that a dog or cat with scabies doesn’t cause serious disease in humans if it infects them. Each variety of the parasite is specific to its host. Thus, a feline mite that comes into contact with human skin might begin to burrow into it but it’ll die. For this reason, these cases are self-limiting and mild.

Risk groups and complications

There’s a more severe form of this disease known as crusted sarcoptic mange. This causes a massive infestation of the parasite (when in most cases the host stores no more than 10 to 15 specimens). The risk groups affected are:

  • People with chronic disorders affecting the immune system such as HIV and chronic leukemia patients
  • Patients with other conditions such as concomitant diseases
  • The elderly, particularly those in nursing homes

In these cases, it’s also possible for patients to experience secondary bacterial infections. As the mite destroys the superficial areas of the skin and causes lesions, it facilitates the entry path for pathogens that couldn’t enter otherwise.

Diagnosis and treatments for scabies in humans

According to the Planned Parenthood website, doctors can detect most cases of human scabies by evaluating the patient’s skin symptoms. In some cases, they may obtain a skin scraping of the affected areas to confirm the diagnosis. This is because samples of mite eggs and feces are visible under a microscope.

The treatment is usually based on ointments one can apply once or twice a day all over the body. All cohabiting members might want to undergo preventive treatment due to the ease of contagiousness of this disease.

The drugs prescribed in most cases are :

  • Permethrin cream, a scabicide used in adults and children over 2 months of age. It’s topical and carries very little risk.
  • Lindane lotion is only suitable for those who didn’t benefit from other approved treatments.
  • Crotamiton is another scabicide available in topical or pill form. As per the Cigna website, this drug has a significant failure rate, so permethrin remains the best option.
  • Finally, ivermectin is for groups at risk and people with crusted scabies.

Tips, prevention, and treatments for scabies

There are many keys to prevent the spread of scabies in humans. Here are some useful tips on the subject:

  • Once the infected person is identified, every direct cohabitant and family member should apply the prescribed topical cream.
  • You must wash all materials in contact with the sick person. The sanitization should be done at 140 degrees Fahrenheit this is the temperature at which the eggs die.
  • Extensive sanitization should be exercised upon completion of the treatment.
  • It’s best to avoid sex until after the completion of treatment.
A clothesline in a field.
Washing bed linen at more than 140 degrees Fahrenheit and subsequent exposure to the sun helps eliminate mites.

There are treatments for scabies in humans

Finally, scabies in humans is a problem linked to the socioeconomic condition of a region. Therefore, it’s much more common in resource-poor tropical countries, where up to 10% of children manifest symptoms. The poorer the health infrastructure, the greater the likelihood of infection.

Fortunately, treatment is usually simple and effective. The extreme sanitization of the environment and the medication of the entire social circle of the affected person is kind of annoying though. However, the parasite could reappear without these measures.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.